The fun of nimble combat in cool battle suits peters out too quickly in the repetitive skirmishes of Warframe.

Creeping through the eerily quiet corridors of an enemy space station, you move with a coiled fluidity. You are a potent weapon, ready to unload a clip, unleash a melee attack, or uncork a powerful elemental ability at a moment's notice. That moment arrives when you come upon one of the robotic menaces or armored soldiers that stand in your way, and then all hell breaks loose. You leap into the fray, sword slashing and guns blazing as you make a hash out of those who would oppose you. Warframe's martial abilities and nimble maneuvers can combine to create satisfying combat, but a tendency toward repetition and sluggish progress dampen this free-to-play brawler's appeal.

In Warframe, you play as a Tenno, a member of a species of ancient warriors that have reemerged to lay waste to the various nefarious species populating the solar system. Your foes include the Grineer, a jackbooted army of deteriorating humanoid clones; the Corpus, a mix-and-match crew of robotic and human parts; and the Infestation, a bunch of shambling organic creatures that vaguely resemble the Flood from the Halo series. While your enemies are visually uninteresting, a lot of the Tenno suits and weapons have a great sense of style that imbues Warframe with a spark of personality. Each species has a cursory backstory, and there is some lore to be found buried in the menus, but there's no narrative thrust or intrigue to speak of. And so you run mission after mission, moving outward from the sun as you level up your loadout and become a more proficient killer.

The core combat of Warframe is straightforward. This is a third-person action game in which you wield two primary weapons and a melee weapon against foes who are largely content to come right at you. You also gain suit powers that allow you to dash and slash through a bunch of enemies, or stun all foes within a certain radius, though these abilities can change drastically depending on what suit you equip. You could unleash fiery maelstroms, turn invisible, create a decoy, use teleportation to switch places with an enemy, or manipulate your foes to fight against their allies. Acquiring new suits, however, requires a significant investment of time or money (more on this later).

Regardless of what powers you have equipped, you can often wage effective war against your enemies by firing on them from a distance, then slicing up the ones who manage to get close. This tactic grows tiresome after a while, however, and doesn't serve you well as you take on tougher levels. Fortunately, you can combine your ability to jump, sprint, and crouch into an acrobatic array of slides, flips, jump kicks, wall runs, leaping slashes, and more. Though there's a certain rigidity to your movement, your mobility is one of the most interesting and enjoyable things about Warframe, and it's fun to zip around your enemies, slashing and shooting until the only ones left standing are your fellow Tenno.

Most suit abilities are accompanied by flashy effects.

You can run Warframe missions with up to three other players, and while flying solo is definitely possible in the early going or when you're grinding for experience or resources, teaming up becomes necessary as you tackle tougher missions. Fighting your way through fiendish hordes with the help of some allies can be very satisfying, especially when there's a good mix of powers in play. Coordinating with friends is the best way to get this kind of experience, because jumping into matches or having folks join you can lead to lopsided situations. If there's a gap in player level or a mismatch with the mission challenge, as often happens, your cooperative missions can devolve into all-out sprints as players easily cut their way through enemies they far outclass.

To minimize such gaps, you can focus on playing only new missions, since those tend to scale toward the upper bound of your capabilities. However, many of the environments in Warframe are reused frequently. You may be taking a different route through an enemy ship or encountering different environmental effects in the asteroid base, but you can't escape seeing the same spaces over and over again. This repetition combines with the lack of enemy variety (each species has only a handful of different units) to make many Warframe missions feel very similar to one another.

To spice things up, you may want to acquire a new gun, a new melee weapon, or a new suit. Warframe is free to play, but you must spend either time or money to acquire new items. Currently, new suits range roughly from $5 to $25, with new weapons falling close to the lower end of that spectrum. Alternatively, you can purchase blueprints to craft new weapons and suits using in-game currency. It takes a significant amount of time to save up the money for a new blueprint, and then you must spend even more time acquiring the resources to actually craft it.

Why walk and shoot when you can slide and shoot?

Even if you skip the lengthy crafting process by using real-world currency, you still have to spend time leveling up your new gear. Jumping into a high-level mission with a brand-new suit is a death sentence, so it's back to lower levels to grind for experience. As your gear levels up, you gain more slots to modify it using boosters picked up during combat. Adding abilities to suits, improving the attributes of your gear, and imbuing your weapon with elemental damage are just some of the things mods can do. Unfortunately, the system to apply and improve mods is poorly laid out and barely explained, leaving you on your own to figure things out.

Some problematic menus pale in comparison to Warframe's real problem: a pervasive tendency toward repetition. Whether you're forging ahead with a high-level suit or leveling up a new one, Warframe repeats enemies, environments, and scenarios too frequently. Without new challenges for your combat abilities, the excitement soon dries up, leaving you without a compelling reason to keep playing. This free-to-play shooter is still technically in beta, so changes may come that make a substantive difference. But as of now, Warframe's interesting combat mechanics are too quickly overcome by the grind of repetition.